The LG RESU (Residential Energy Storage Unit) has established itself as one of the most trusted home energy storage systems in the solar energy market. As homeowners increasingly seek energy independence and backup power solutions, understanding the complete LG RESU lineup becomes crucial for making an informed investment decision.
This comprehensive guide covers everything you need to know about LG RESU batteries in 2025, from the latest models and technical specifications to real-world performance data and cost analysis. Whether you’re considering your first home battery or expanding an existing system, this guide will help you navigate the complex world of residential energy storage.
What is LG RESU?
RESU stands for Residential Energy Storage Unit, LG’s flagship line of lithium-ion home batteries designed to store excess solar energy and provide backup power during outages. These DC-coupled battery systems have been powering homes since 2018, when LG Energy Solution (formerly LG Chem) entered the residential energy storage market.
LG Energy Solution vs LG Chem: The Brand Evolution
In 2021, LG Chem spun off its battery division to create LG Energy Solution, a dedicated entity focused exclusively on energy storage systems. This strategic move allowed the company to concentrate on rapidly evolving battery technologies and energy management solutions. While older RESU models may still carry the LG Chem branding, all current production falls under LG Energy Solution.
Market Position and Reputation
LG RESU batteries have earned a reputation for reliability and performance in the competitive home battery market. The company leverages over six decades of electronics manufacturing experience and supplies batteries to major electric vehicle manufacturers, including the Chevrolet Bolt. This automotive-grade technology translates into robust, long-lasting home energy storage solutions.
Why Homeowners Choose LG RESU Systems
- Proven Reliability: Automotive-grade lithium-ion technology with extensive real-world testing
- Compact Design: Space-efficient form factor suitable for indoor and outdoor installation
- High Efficiency: Up to 97.5% round-trip efficiency in DC-coupled configurations
- Scalable Solutions: Modular design allows for system expansion as energy needs grow
- Strong Warranty: Industry-leading 10-year warranty with capacity retention guarantees
Complete LG RESU Product Lineup (2025)
LG’s current battery portfolio spans multiple generations and configurations, each designed for specific applications and system requirements. Understanding the differences between these models is essential for selecting the right solution for your home.
Current Generation Models
RESU10H Prime (9.6 kWh)
The RESU10H Prime represents the third generation of LG’s residential battery technology, offering 9.6 kWh of usable energy in a compact, modular design. Key specifications include:
- Usable Energy: 9.6 kWh
- Continuous Power: 5.0 kW
- Peak Power: 7.0 kW (10 seconds)
- Voltage Range: 350-450V DC
- Dimensions: 19.8″ × 32.2″ × 11.6″
- Weight: 244 lbs
- Efficiency: 94.5-97.5% round-trip
RESU16H Prime (16 kWh)
The RESU16H Prime offers the highest capacity in LG’s residential lineup, providing substantial energy storage for whole-home backup applications:
- Usable Energy: 16.0 kWh
- Continuous Power: 7.0 kW
- Peak Power: 11.0 kW (10 seconds)
- Voltage Range: 350-450V DC
- Dimensions: 19.8″ × 42.8″ × 11.6″
- Weight: 352 lbs
- Efficiency: 94.5-97.5% round-trip
LG FLEX Modular System
The LG FLEX introduces a revolutionary modular approach to home energy storage, featuring:
- Usable Energy: 8.6 kWh, 12.9 kWh, or 17.2 kWh configurations
- Modular Design: Separate battery control unit and battery modules
- Easy Maintenance: Detachable control unit for on-site replacement
- Flexible Installation: Improved handling and transportation
enblock Series
The enblock series represents LG’s 48V battery solutions, designed for compatibility with low-voltage hybrid inverters:
- enblock C6.5: 6.5 kWh total, 5.9 kWh usable
- enblock C10: 9.8 kWh total, 8.8 kWh usable
- enblock C12: 13.1 kWh total, 11.7 kWh usable
- enblock E series: 12.4 kWh and 15.5 kWh configurations
Legacy Models Still Available
RESU10H (9.8 kWh)
The second-generation RESU10H remains available in some markets, offered in two variants:
- RESU10H-R: Compatible with SMA and other residential inverters
- RESU10H-C: Designed for commercial and three-phase applications
- Capacity: 9.8 kWh total, 9.3 kWh usable
- Warranty: 60% capacity retention after 10 years
RESU13 (13.1 kWh)
The RESU13 bridges the gap between the 10H and 16H models:
- Total Energy: 13.1 kWh
- Usable Energy: 12.4 kWh
- Voltage: 48V system
- Applications: Mid-size residential installations
Discontinued Models (For Reference)
Several early RESU models have been discontinued but may still be found in existing installations:
- RESU6.5: Entry-level 6.5 kWh system
- RESU3.3: Compact 3.3 kWh solution
Technical Specifications Deep Dive
Battery Chemistry and Technology
All LG RESU batteries utilize NMC (Nickel Manganese Cobalt) lithium-ion chemistry, the same technology found in premium electric vehicles. This chemistry offers several advantages:
- High Energy Density: More energy storage in a smaller footprint
- Long Cycle Life: Thousands of charge/discharge cycles
- Thermal Stability: Safe operation across wide temperature ranges
- Low Self-Discharge: Minimal energy loss during storage
Capacity vs Usable Energy Explained
Understanding the difference between total capacity and usable energy is crucial for proper system sizing:
- Total Capacity: The theoretical maximum energy storage
- Usable Energy: The actual energy available for household use
- Depth of Discharge (DoD): LG RESU systems typically offer 95% DoD
- Reserve Capacity: Maintained to protect battery longevity
Voltage Configurations
LG offers batteries in two primary voltage configurations:
400V High Voltage Systems
- Models: RESU10H Prime, RESU16H Prime, FLEX
- Advantages: Higher efficiency, faster charging, better inverter compatibility
- Applications: Larger residential and light commercial installations
48V Low Voltage Systems
- Models: enblock C series, RESU13
- Advantages: Broader inverter compatibility, easier installation
- Applications: Smaller residential systems, retrofit applications
Power Output Ratings
LG RESU batteries provide both continuous and peak power capabilities:
- Continuous Power: Sustained output for normal household loads
- Peak Power: Short-duration output for high-demand appliances
- Surge Capability: Ability to handle motor starting currents
Round-Trip Efficiency
LG RESU systems achieve industry-leading efficiency ratings:
- DC-Coupled Systems: 94.5-97.5% efficiency
- Efficiency Benefits: Lower energy losses, reduced operating costs
- Real-World Performance: Maintains high efficiency across temperature ranges
Installation and Compatibility
DC-Coupled vs AC-Coupled Systems
Most LG RESU batteries are designed as DC-coupled systems, offering several advantages:
DC-Coupled Benefits
- Higher Efficiency: Fewer power conversions reduce energy losses
- Lower Cost: Single inverter handles both solar and battery
- Simplified Design: Fewer system components
DC-Coupled Limitations
- Inverter Dependency: Requires compatible hybrid inverter
- Retrofit Challenges: May require inverter replacement
- Limited Flexibility: Battery and solar must share inverter capacity
Compatible Inverter Brands and Models
LG RESU batteries work with leading inverter manufacturers:
High Voltage (400V) Compatible Inverters
- SolarEdge: StorEdge series hybrid inverters
- SMA: Sunny Boy Storage and Sunny Island series
- Fronius: Symo Hybrid and Primo Hybrid models
- Goodwe: Hybrid inverter series
Low Voltage (48V) Compatible Inverters
- Victron Energy: MultiPlus and Quattro series
- Schneider Electric: Conext SW and XW+ series
- Outback Power: FXR and Radian series
- Sol-Ark: Hybrid inverter models
Installation Requirements
Indoor Installation
- Temperature Range: 32°F to 104°F (0°C to 40°C)
- Ventilation: Adequate airflow for thermal management
- Clearances: Minimum spacing requirements for safety
- Mounting: Wall-mount or floor-standing options
Outdoor Installation
- Enclosure Rating: IP55 protection against dust and water
- Shade Requirements: Protection from direct sunlight recommended
- Temperature Considerations: Performance may be reduced in extreme temperatures
Professional Installation Considerations
LG RESU installation requires certified professionals due to:
- High Voltage Systems: 400V DC presents electrical hazards
- Permit Requirements: Local electrical permits typically required
- Code Compliance: Must meet NEC and local electrical codes
- Warranty Protection: Professional installation required for warranty coverage
Performance and Real-World Testing
Actual vs Rated Performance
Real-world testing reveals how LG RESU systems perform under typical operating conditions:
Capacity Performance
- Initial Capacity: Systems typically deliver 98-100% of rated capacity when new
- Temperature Effects: 5-10% capacity reduction in extreme temperatures
- Age-Related Degradation: Gradual capacity loss over time
Power Output Performance
- Continuous Power: Maintains rated output under normal conditions
- Peak Power Duration: Can sustain peak output for specified durations
- Voltage Stability: Maintains stable output voltage throughout discharge
Charging and Discharging Efficiency
Independent testing confirms LG RESU efficiency claims:
- Round-Trip Efficiency: 94.5-97.5% depending on model and conditions
- Charging Efficiency: 98-99% DC charging efficiency
- Discharging Efficiency: 97-98% DC discharging efficiency
Climate Performance
LG RESU batteries demonstrate robust performance across climate zones:
Hot Climate Performance
- Capacity Impact: 5-8% reduction above 95°F (35°C)
- Cycle Life: Accelerated aging in sustained high temperatures
- Mitigation Strategies: Shade installation, adequate ventilation
Cold Climate Performance
- Capacity Impact: 10-15% reduction below 32°F (0°C)
- Power Limitations: Reduced power output in extreme cold
- Recovery: Performance returns to normal as temperature rises
Cycle Life and Degradation Patterns
Long-term monitoring reveals predictable degradation patterns:
- Initial Degradation: 2-3% capacity loss in first year
- Linear Degradation: 1-2% annual capacity loss thereafter
- Cycle Count: 6,000+ cycles to 80% capacity retention
- Calendar Aging: Time-based degradation independent of cycling
Pricing and Cost Analysis (2025)
LG RESU battery pricing varies by model, market conditions, and installation complexity:
Current Market Pricing by Model
Equipment Costs (Before Installation)
- RESU10H Prime: $7,000 – $9,000
- RESU16H Prime: $10,000 – $13,000
- enblock C10: $6,000 – $8,000
- enblock C12: $7,500 – $9,500
Total Installed Costs
- RESU10H Prime: $9,000 – $13,000 installed
- RESU16H Prime: $11,000 – $16,000 installed
- Cost per kWh: $900 – $1,300 per kWh of usable capacity
Installation Cost Variables
Several factors influence total installation costs:
- Electrical Upgrades: Panel upgrades, new circuits, permits
- Inverter Compatibility: May require inverter replacement or upgrade
- Site Complexity: Difficult access, long wire runs, structural modifications
- Local Labor Rates: Regional variations in installation costs
- Permit Fees: Local jurisdiction requirements
Federal Tax Credit Eligibility
LG RESU batteries currently qualify for federal tax incentives, though significant changes are pending:
- 30% Federal Tax Credit: Currently available but under threat
- Potential Termination: Congress may end the credit by December 31, 2025
- Standalone Eligibility: Batteries qualify even without solar panels (as of 2023)
- Maximum Benefit: No cap on credit amount
- Urgent Action Required: Systems must be installed and inspected by December 31, 2025 to potentially qualify
Given the potential changes to federal tax credits, homeowners interested in battery storage should act quickly to ensure their systems are installed and inspected by December 31, 2025.
State and Local Incentive Programs
Additional incentives may be available depending on location:
California Programs
- SGIP (Self-Generation Incentive Program): Up to $1,000 per kWh
- CARE/FERA Customers: Enhanced incentive rates
- Disadvantaged Communities: Additional incentive tiers
Other State Programs
- Massachusetts: SMART program battery adders
- New York: NY-Sun battery incentives
- Hawaii: Battery Bonus program
- Vermont: Renewable Energy Incentive Program
ROI Calculations and Payback Periods
Return on investment varies significantly based on local utility rates and usage patterns:
Time-of-Use Arbitrage
- Typical Savings: $500 – $1,500 annually
- Payback Period: 8-15 years without incentives
- Best Markets: High TOU rate differentials
Backup Power Value
- Avoided Costs: Food spoilage, lost productivity, generator fuel
- Comfort Value: Difficult to quantify but significant
- Insurance Reduction: Some insurers offer discounts
Warranty and Support
Warranty Terms by Model
LG provides comprehensive warranty coverage across its RESU lineup:
Prime Series Warranty
- Duration: 10 years from installation date
- Capacity Retention: 70% of rated capacity guaranteed
- Energy Throughput: 22.4 MWh total energy limit
- Coverage: Defects in materials and workmanship
Legacy Model Warranty
- RESU10H (Gen 2): 60% capacity retention after 10 years
- enblock Series: 60-70% retention depending on model
- Energy Limits: Varies by model and generation
What’s Covered vs Excluded
Warranty Coverage Includes
- Manufacturing Defects: Materials and workmanship issues
- Capacity Degradation: Below specified retention levels
- Component Failures: BMS, contactors, and internal components
- Replacement Costs: Parts and reasonable labor
Warranty Exclusions
- Misuse or Abuse: Operation outside specifications
- Environmental Damage: Flooding, fire, lightning, etc.
- Unauthorized Modifications: DIY repairs or modifications
- Normal Wear: Degradation within warranty parameters
Warranty Claim Process
Filing a warranty claim involves several steps:
- Contact Installer: Initial troubleshooting and documentation
- LG Technical Support: Remote diagnostics and analysis
- Claim Submission: Formal warranty claim with supporting data
- Resolution: Repair, replacement, or credit as appropriate
Customer Support and Service Network
LG maintains a comprehensive support infrastructure:
- Technical Hotline: Direct access to battery specialists
- Certified Installer Network: Trained service technicians
- Remote Monitoring: Many systems support remote diagnostics
- Online Resources: Manuals, troubleshooting guides, FAQs
LG RESU Technical Specifications
Enphase IQ Battery Comparison
| Feature | LG RESU10H Prime | Enphase IQ Battery 5P |
|---|---|---|
| Usable Capacity | 9.6 kWh | 5.0 kWh |
| Continuous Power | 5.0 kW | 3.84 kW |
| Modularity | Limited | Highly modular |
| Installation | Professional required | Simpler installation |
| Monitoring | System-level | Individual battery monitoring |
Generac PWRcell Comparison
The Generac PWRcell offers a different approach with its modular cabinet design:
- Capacity Range: 9-18 kWh in 3 kWh increments
- Integrated Inverter: All-in-one solution
- Backup Capability: Designed for whole-home backup
- Cost: Generally higher than LG RESU
Use Cases and Applications
Backup Power Scenarios
LG RESU batteries excel in various backup power applications:
Essential Loads Backup
- Typical Runtime: 8-24 hours depending on load
- Supported Loads: Lights, refrigeration, communications, medical equipment
- System Sizing: RESU10H Prime sufficient for most essential loads
Whole Home Backup
- Capacity Requirements: RESU16H Prime or multiple units
- Power Limitations: May not support all high-power appliances simultaneously
- Duration: 4-12 hours depending on usage
Solar Self-Consumption Optimization
Maximizing solar energy utilization is a primary application:
- Peak Shaving: Store excess midday solar production
- Evening Usage: Discharge stored energy during peak demand periods
- Seasonal Variations: Adjust charging/discharging patterns
- Weather Adaptation: Optimize for cloudy day performance
Time-of-Use Rate Arbitrage
LG RESU systems can reduce electricity costs through strategic charging and discharging:
Rate Structure Analysis
- Peak Periods: Typically 4-9 PM on weekdays
- Off-Peak Periods: Late night and early morning hours
- Rate Differentials: $0.20-0.50 per kWh difference in some markets
Optimization Strategies
- Charge During Off-Peak: Lowest cost energy storage
- Discharge During Peak: Maximum cost avoidance
- Solar Priority: Prefer solar charging when available
For homeowners looking to maximize savings through time-of-use rate arbitrage, LG RESU systems provide an effective solution for storing energy during low-cost periods and using it during expensive peak hours.
Off-Grid Applications
While primarily designed for grid-tied applications, LG RESU batteries can support off-grid systems:
- Remote Homes: Primary energy storage for off-grid solar systems
- Backup Generators: Reduce generator runtime and fuel consumption
- Seasonal Homes: Maintain power during owner absence
- System Sizing: Typically requires multiple batteries for adequate capacity
Buying Guide and Recommendations
How to Size Your Battery System
Proper system sizing is critical for optimal performance and cost-effectiveness:
Energy Needs Assessment
- Analyze Usage Patterns: Review 12 months of utility bills
- Identify Essential Loads: Determine critical vs. non-critical loads
- Calculate Daily Consumption: Average kWh per day
- Consider Seasonal Variations: Peak usage periods
Backup Duration Requirements
- Short Outages: 4-8 hours (RESU10H Prime sufficient)
- Extended Outages: 12-24 hours (RESU16H Prime recommended)
- Multi-Day Outages: Multiple batteries or generator backup
Solar Integration Considerations
- Solar Production: Match battery capacity to excess solar generation
- Seasonal Variations: Account for winter production decreases
- Shading Issues: Consider impact on charging capability
Which LG RESU Model to Choose
RESU10H Prime – Best For:
- Small to Medium Homes: 1,500-2,500 sq ft
- Essential Loads Backup: Refrigeration, lights, communications
- Budget-Conscious Buyers: Lower upfront investment
- Limited Space: Compact installation footprint
RESU16H Prime – Best For:
- Large Homes: 2,500+ sq ft
- Whole Home Backup: Support more loads simultaneously
- High Energy Users: Above-average electricity consumption
- Future Expansion: Room for increased energy needs
enblock Series – Best For:
- Retrofit Applications: Existing solar systems with microinverters
- 48V Inverter Systems: Compatibility with low-voltage equipment
- Modular Growth: Start small and expand over time
- Budget Applications: Lower cost per kWh in some configurations
Finding Certified Installers
Selecting the right installer is crucial for system performance and warranty protection:
LG Certified Installer Network
- Training Requirements: Completed LG battery installation courses
- Certification Levels: Different levels based on experience
- Warranty Protection: Installation warranty coverage
- Technical Support: Access to LG technical resources
Installer Selection Criteria
- Experience: Minimum 5+ battery installations
- Licensing: Valid electrical contractor license
- Insurance: Adequate liability and workers compensation
- References: Recent customer testimonials
- Local Presence: Available for ongoing service
Questions to Ask Installers
Important questions to evaluate potential installers:
Technical Questions
- How many LG RESU systems have you installed?
- What inverter do you recommend for my application?
- How will you handle system monitoring and maintenance?
- What permits are required for my installation?
Business Questions
- Are you LG certified and properly licensed?
- What warranties do you provide on installation?
- How do you handle warranty claims and service calls?
- Can you provide local references?
Red Flags to Avoid
Warning signs of problematic installers:
- Door-to-Door Sales: Aggressive sales tactics
- Pressure to Sign: “Limited time” offers
- Unusually Low Bids: May indicate cutting corners
- No Local Presence: Difficult to reach for service
- Poor Communication: Unresponsive to questions
- No References: Unable to provide customer references
Conclusion
The LG RESU battery lineup represents a mature, reliable solution for residential energy storage needs. With multiple models spanning different capacities and voltage configurations, there’s likely an LG RESU system suitable for most home applications.
The RESU10H Prime offers an excellent balance of capacity, performance, and value for typical residential applications, while the RESU16H Prime provides the highest capacity for larger homes or extended backup requirements. The enblock series fills important niches for retrofit applications and systems requiring 48V compatibility.
Key factors favoring LG RESU systems include:
- Proven reliability with automotive-grade components
- High efficiency DC-coupled design
- Comprehensive warranty with strong manufacturer support
- Competitive pricing relative to performance
- Broad installer network for professional installation and service
However, potential buyers should also consider the limitations, including inverter compatibility requirements and the need for professional installation. The DC-coupled design, while efficient, may not be suitable for all retrofit applications.
As the residential energy storage market continues to evolve, LG Energy Solution’s commitment to battery technology innovation and manufacturing excellence positions the RESU lineup as a solid choice for homeowners seeking reliable, long-term energy storage solutions.
For those considering an LG RESU system, we recommend starting with a comprehensive energy audit, consulting with certified installers, and carefully evaluating local utility rates and incentive programs to optimize the return on investment. Given the potential changes to federal tax credits, homeowners interested in battery storage should act quickly to ensure their systems are installed and inspected by December 31, 2025.